1. Technical Field
This invention relates to security systems, and more particularly to security systems for monitoring a surveillance area and including transmitters, carried by users, sensing stations for receiving RF signals from actuated transmitters and directable monitoring stations for immediately providing video signals of the area where the user actuated the transmitter and audio communication.
2. Background
Criminals know that response times of security personnel and police are relatively slow as compared with the time required to commit a crime and escape, particularly in isolated areas. As a result, isolated areas, such as parking garages and lots, experience higher crime rates, especially late at night.
Conventional video surveillance systems typically employ mounted camera(s) which generate video signals for display on monitor(s) at a central location. Surveillance cameras are typically located in vulnerable areas such as doorways, parking garages and lots, etc. and have been mounted on platforms which pan and tilt in response to manual control or pre-established programs.
Conventional security systems employing direction finding antennas which locate actuated transmitters using signal triangulation are disclosed in U.S. Pat. No. 4,954,836, entitled "Follow-Up System for Moving Bodies" to Sakuma and U.S. Pat. No. 5,225,809, entitled "Personal Security System and Apparatus Therefore" to Bunn. The security system in Sakuma .utilizes both directional and non-directional antenna/receiver systems. At least two non-directional antenna/receiver systems having the two strongest received signals are selected when a transmitter is actuated. The directional antenna/receiver systems associated with the selected non-directional antenna/receiver systems rotate direction-finding antennas until maximum signals are received. The security system then performs signal triangulation to determine the location of the actuated transmitter. A central computer displays the location of the actuated transmitter. The security system performs tracking if the transmitter is actuated continuously.
Conventional security systems with direction finding antennas still fail to respond quickly enough to significantly reduce or prevent crimes in isolated areas. While such direction finding systems locate an actuated transmitter immediately and provide the location on a grid map at a control station, such security systems do not provide immediate assistance to the user actuating the transmitter. Response times are typically too long to stop the crime in the early stages, most importantly before significant harm can occur. If security personnel or police arrive after the suspect leaves the scene of the crime, the suspect has a high probability of escape since such security systems do not help identify the fleeing suspect and valuable time can be lost. Conventional security systems are prone to false alarms since each time a transmitter is actuated, security personnel or police must assume that the alarm is real and respond by sending help to the location of the actuated transmitter.
Therefore, a security system which addresses the above-described problems, among others, is desirable.